1. Field of the Invention
The invention pertains to seals, more specifically to a seal for casting in a concrete wall of a container of a septic system fluid distribution system, that forms an opening through the concrete wall that is closed by the seal.
2. Description of the Prior Art
U.S. Pat. No. 5,286,040 patented Feb. 15, 1994 by N. W. Gavin describes a unitary molded seal comprising a cylindrical outer wall and a cup-shaped seal attached to a first end of the cylindrical wall at the open end of the cup. The seal is held in the mold for a wall of a concrete container by a cup-shaped protrusion that extends from a first wall of the mold into the open end of the cup. The first wall contacts the first end of the cylindrical wall, and a second wall of the mold contacts the second end of the cylindrical outer wall so that the cylindrical wall forms the opening in the hardened concrete wall and lines the full length of the opening.
When the cylindrical wall is shorter than the distance between the first and second walls of the mold, a concrete flash covers part or all of the opening adjacent to the bottom of the cup.
A ring extends radially from the cylindrical outer wall. The ring anchors the cylindrical wall in the concrete wall against axial thrust of pipe when pipe is inserted through an opening in the bottom of the cup which is made by tearing out a portion of the bottom sealing wall of the cup.
U.S. Pat. No. 3,815,214 patented Jun. 11, 1974 by Kyle, Sr. describes a pair of frustoconical shells supporting an annular resilient O-ring on an annular groove that is semicircular in cross section. The O-ring supporting groove is formed by quarter-circle in cross section annular grooves, one on one end of each shell which abut to form the semicircular groove when the two frustoconical shells are drawn together by a bolt which passes through the outer wall of the concrete form, through one shell, and screws into the other shell. The mold outer wall, pair of shells, and mold inner wall form a hole through the concrete wall when the wall is molded. When the shells are withdrawn from the molded wall, the inner wall of the hole mirrors the shape of the joined shells and contains the O-ring the outer circumference of which is embedded in an annular groove, half-circle in cross section, in the concrete.
U.S. Pat. No. 4,650,149 patented Mar. 17, 1987 by Poulette et al. describes a metal cylinder extending to an inside wall and an outside wall of a form for a concrete wall. The metal cylinder is surrounded by a flexible rubber or elastomeric sleeve that extends to the inside wall and the outside wall. A narrow gasket surrounds the sleeve. The inner diameter of the gasket comprises an annular ring, arrowhead in cross section, that is embedded in an annular groove around the sleeve. The outer diameter of the gasket is T-shaped in cross section, for being molded into the concrete as an annular anchor for the gasket. After the concrete is poured between the inside and outside walls of the form, and sets, bolts holding the metal cylinder between the walls are removed, the form walls are removed, the metal cylinder is removed, and the rubber sleeve is pulled radially inward off the annular ring and is withdrawn from the hole through the concrete wall made by the sleeve on the cylinder.
It is one object of the invention to provide a seal for casting in a concrete wall comprising a first tubular outer wall element molded with one end of a cup shaped element designed for receiving pipe through the bottom of the cup, and a second, independent tubular element inserted between the first tubular outer wall element and an outer wall of the cup shaped element.
It is another object of the invention to provide a seal for casting in a concrete wall comprising a first tubular element having a first open end and a second sealing end adapted for sealing around pipe, the first end being molded, preferably integrally molded, with a first end of a second tubular element, the second sealing end extending into the second tubular element, and a third tubular element extending between the first tubular element and the second tubular element. Preferably the third tubular element is made of a stiffer material than the integrally molded first and second tubular elements. Preferably the third tubular element is removably inserted between the first and second tubular elements.